Endo seeks tougher standards for generic versions of Lidoderm

By Alaric DeArment

CHADDS FORD, Pa. — Endo Pharmaceuticals is hoping the Food and Drug Administration will back tougher regulatory approval requirements for generic versions of one of its drugs.

The drug maker added an amendment to a citizen petition it filed with the FDA in 2006 concerning the drug Lidoderm (lidocaine), a patch used to treat post-herpetic neuralgia, a painful condition associated with shingles. The drug maker said the amended petition "highlights the growing scientific and regulatory support" for requiring clinical studies from generic drug makers looking to gain FDA approval for generic versions of such locally acting topical drugs as Lidoderm.

"Since we filed the original citizen petition in 2006, new studies and opinions from research scientists, as well as public statements from FDA officials, have further validated the need for comparative clinical endpoint studies to ensure a locally acting topical medication is bioequivalent to the branded product," Endo chief scientific officer and EVP research and development Ivan Gergel said. "FDA must publicly address the many unanswered questions from the original petition, as well as the additional concerns raised in this amendment, before taking any formal steps toward the approval of a generic version of Lidoderm."

Specifically, Endo said pharmacokinetic studies, which measure the level of a drug in the bloodstream, are not enough to demonstrate that a generic version of Lidoderm would be equivalent to the branded drug. The company also said that scientists had not identified any method other than clinical endpoint studies to show that drugs like Lidoderm and generic versions are equivalent and asked the agency to address allegations by another drug maker that the FDA had answered Endo's 2006 petition in private correspondence, which Endo said would be illegal if it's true.